This page explains how Qi Guo (USATT# 80876)'s rating went from 1945 to 1940 at the Westchester 2013 October Open held on - 27 Oct 2013. The links below take you to pages that describe various aspects of the rating processor.

The rating processor goes through 4 passes in order. The links take you to pages that provide detailed explanations of the calculations during each of the 4 passes.